Cushion attachments for stadium and similar seats



Aug. 16, 1955 D. L. LUKENS 2,715,434

CUSHION ATTACHMENTS FOR STADIUM AND SIMILAR SEATS Filed March 23, 1955 4 Sheets-Sheet 1 1 N VENTOR A'ITUAAEY Aug. 16, 1955 D. L. LUKENS CUSHION ATTACHMENTS FOR STADIUM AND SIMILAR SEATS Filed March 23, 1955 4 Sheets-Sheet 2 BY N. bA-QAM/ ATTORNEY D. L. LU KENS Aug. 16, 1955 CUSHION ATTACHMENTS FOR STADIUM AND SIMILAR SEATS Filed March 23, 1955 4 Sheets-Sheet I5 ATTORNEY D. L. LUKENS Aug. 16, 1955 CUSHION ATTACHMENTS FOR STADIUM AND SIMILAR SEATS Filed March 23, 1953 4 Sheets-Sheet 4 ATTORNEY United States Patent CUSHION ATTACHM'ENTS FOR STADIUM AND SIMILAR SEATS David L. Lukens, South Orange, N. J., assignor, by mesne assignments, to McLaney Manufacturing Corporation, Miami Beach, Fla., a corporation of New York Application March 23, 1953, Serial No. 344,151

Claims. (Cl. 155-131) The present invention relates to cushion attachments for stadium and similar seats and more particularly to means for providing coin control for a cushion pad which is normally secured immovably in inoperative position on the under side of a seat bottom and which is releasable for movement to operative position on the upper side of the seat bottom upon actuation of the coin control mechanism.

A principal object of the invention is to provide the customarily uncushioned, generally wooden or metal, and hence uncomfortable seats of ball parks and similar stadiums with permanently attached cushions locked in inoperative position beneath the seats and available for movement to operative position on the seats when the prospective occupants of the individual seats deposit proper coins in lock-releasing means associated with the seats.

Related objects are to provide locked and releasable cushion pads of the type indicated with coin-collecting mechanism which will be inexpensive to manufacture, easy to install in existing seats Whether made of wood or metal, which will be simple and foolproof in construction, which can be readily operated by any patron, which will unfailingly refuse to operate upon the deposit of any coin of insufficient value, which are substantially tamperproof, and which can be quickly and easily serviced after use for collection of deposited coins and restoration to locked inoperative position for a repetition of the coin-deposit, use and coin-collection cycle.

Other objects and advantages of the invention will be apparent from the following description of certain preferred embodiments which are illustrated in the accompanying drawings, in which Figure 1 is a perspective view of a folding type chair or seat of the kind commonly used in outdoor places of public assembly and entertainment, with the seat bottom shown folded and with a preferred form of the cushion and related mechanism of the present invention shown locked in inoperative position;

Fig. 2 is a similar perspective view of the same seat with the seat bottom opened to operative position and with the cushion disposed for use thereon;

Fig. 3 is a bottom plan view of the seat bottom with the cushion locked in inoperative position, or it may be considered a front elevational view of the seat bottom in folded or raised inoperative position with the cushion locked in inoperative position thereon;

Fig. 4 is a longitudinal or fore and aft cross-sectional view of Fig. 3, taken along the line 4-4 thereof;

Fig. 5 is a similar view showing the seat bottom swung to horizontal, operative position, with the cushion remaining locked in inoperative position on the under side of the bottom;

Fig. 6 is a view similar to that of Fig. 5, with however the cushion unlocked and moved to operative position on the top surface of the seat bottom;

Fig. 7 is an exploded perspective view of the coinice controlled lock and its mode of attachment to the seat and the cushion;

Fig. 8 is a front elevational view of the assembled coin box with the actuating slide released to its normal position of rest with the cushion locked in inoperative position, and showing a coin about to be inserted for unlocking the cushion;

Fig. 9 is a relatively enlarged vertical central crosssectional view taken on the line 9-9 of Fig. 8;

Fig. 10 is a front elevational view of the working parts of the lock, shown with the front cover plate removed and with the parts in the position in which they are shown in Fig. 8 except that the operating handle has been moved as far to the left as possible with no coin inserted;

Fig. 11 is a similar view but showing the coin inserted and the actuating and locking slides moved to unlocking position;

Fig. 12 is a horizontal cross-sectional view taken on the line 12-12 of Fig. 10;

Fig. 13 is a horizontal cross-sectional view taken on the line 13-13 of Fig. 11;

Fig. 14 is a detail view of a modified form of connection for the coin box and the cushion slide rod;

Fig. 15 is a view looking down in plan on the detail of Fig. 14;

Fig. 16 is a view like that of Fig. 3 but showing a modification;

Fig. 17 is a perspective view of the cushion shown in Fig. 16;

Fig. 18 is a vertical central cross-sectional view taken on the line 18-18 of Fig. 16;

Fig. 19 is a perspective view of the coin box and cushion slide rod of Fig. 16;

Fig. 20 is a vertical central cross-sectional view like that of Fig. 6 but showing the cushion of Fig. 16 in the process of being moved to fully operative position; and

Fig. 21 is a view like that of Fig. 20 but showing the cushion in fully operative position with the back cover disposed over the seat backrest.

But these illustrations depict simply certain exemplary embodiments which have been reduced to practice and found to give entirely satisfactory and reliable results and which accordingly are at present preferred. The inventive principles may be incorporated in other and different constructions within the spirit of the invention and the scope of the appended claims.

Generally speaking, the invention comprises providing any standard type of cushionless chair, particularly such as are intended for public, spectator occupancy as in grandstands, stadiums and the like, with a cushion pad permanently secured to the seat bottom and normally locked in inoperative position on the under surface thereof by coin-controlled means which can be actuated to release the pad and permit it to be disposed, while still captive on the chair, in operative position on the upper surface of the seat bottom.

Important details of the invention are concerned with providing an extremely simple and inexpensive coincontrolled lock and means for attaching the lock to the cushion and to the chair, so that the lock and attachment means can be mass-produced at low cost, and installed and serviced (for removal of the deposited coins and to restore the cushions to locked position for re-use on deposit of more coins) at such low cost as to yield a high return on the capital investment and operating expenses when formed for operation on a coin of low value, such for example as a twenty-five cent piece.

In the embodiment illustrated in Figs. l13, the reference numeral 1 designates generally a chair or seat of the kind customarily provided in large numbers for spectator occupancy in outdoor installations, here shown as being of the uplift type having the usual back 2 secured between side standards 3 which also provide pivoted support for a seat bottom member 4. The latter is customarily made of stout wooden slats mounted transversely on side brackets and appropriately dished or contoured, or it may consist of a metal pan of generally similar overall shape. The seat bottom is cushionless as installed and is occupied without cushion by the patron who pays only the established admission fee. As has been explained, the present invention provides a cushion attachment which is available for use by individual occupants who pay an additional charge therefor.

The cushion is provided in the form of a generally rectangular pad 5 which may comprise a waterproof ticking of such sheet material as artificial leather enveloping a soft fill of suitable upholstery stuffing such as a sheet of sponge rubber. This pad is made permanently captive on the seat bottom as by means of a flexible tongue 6, which may be triangular in shape, formed of the covering material of the pad, extending integrally from the base of the triangle which is common with one of the four side edges of the pad. With the tongue folded flat behind the pad, and an eye 7 formed in the apex of the triangle and slipped over a rod 8 which is secured at its opposite ends to the front and rear edges of the seat bottom 4 (by means hereinafter to be explained), the cushion pad is permanently captive on the seat for movement (unless restrained by a connection additional to that of the eye 7 and rod 8) between the under side of the seat bottom as shown in Fig. 1 and the top side thereof as shown in Fig. 2.

The rod 8 is anchored at its lower or rear end to the rear edge of the seat bottom by a bracket number 9 which, in the embodiment shown, comprises a rearwardly extending hook 10 for engaging under the rear edge of the seat bottom and a forwardly extending hook 11 which is spaced from and generally parallel to the rod for forming therewith a pocket into which the lower or back edge margin of the cushion may be tucked and held, as shown in Fig. 1, when the cushion is in inoperative position under the seat bottom.

The upper or forward end of the rod 8 is anchored to the forward edge of the seat bottom by being fastened in a coin box 12. In the present form, as best illustrated in Fig. 7, this box is comprised of a back plate 13 having at its top a rearwardly projecting hook 14 which is caught over the front edge of the seat bottom; or the back plate 13 may simply be perforated and afi ixed to the seat bottom by countersunk wood screws. In either case the back plate has forwardly flanged side and bottom edges. A nut 15 may be turned on the threaded end 16 of the rod 8 after insertion through a hole 17 in the bottom flange of the back plate, so that the rod can be fitted to seats of varying front to rear length by disposing more or less of the threaded end 16 of the rod inside the coin box and tightening up on the nut to tension the rod securely between the hooks 10 and 14.

The plate 13 may be further secured to the seat bottom by a screw 18 standing through a slot 19 in the plate and through a shim 20 and into the wood or other material of the seat bottom. With these connections covered and protected from tampering by the coin box front plate 21, it will be evident that the rod is securely and permanently held in place and the cushion is captive thereon for movement (when not additionally or otherwise locked) along the rod for disposition in the two positions shown in Figs. 1 and 2.

As has been explained, the cushion is normally locked in the inoperative position shown in Fig. l and is intended to be released by a patron for movement to the operative position shown in Fig. 2 upon deposit of a coin of predetermined value in the coin box 12. Accordingly, the coin box is required normally to hold the end or edge margin of the cushion opposite that from which the tongue 6 extends and to release its hold responsive to the depositing of a coin, and for this purpose the normally upper edge of the cushion, which is disposed adjacent the front edge of the seat bottom when the cushion is in inoperative position, has projecting from it, as by being sewed or riveted to it, a fitting in the form of a stout tab 24 or leather or the like terminating in a generally T-shaped lug 25. This lug is adapted to be inserted through a slot 26 in the coin box front plate 21 and to be latched or locked therein by mechanism which can be released only upon actuation responsive to depositing a coin in the box. When the lug is thus held in the slot it will be evident that the cushion is secured in the inoperative position shown in Fig. 1, so that it is impossible to move the cushion to the operative Fig. 2 position. To hold the lug in the slot and to release it as explained, the invention contemplates providing any suitable coincontrolled locking or latching mechanism in the coin box. A highly satisfactory mechanism, comprising a simple assembly of a minimum number of parts, which we have used with success in actual practice, will now be described.

Contained within the coin box 12, conveniently and preferably by being mounted as a unit on the removable front cover plate 21, is the mechanism better shown in the disassembled, exploded perspective view of Fig. 7. This comprises a locking slide 30, an acutating or handle slide 31, a filler or hearing bar 32, a detent plate 33, a spring 34, and a camming finger 35, all formed in the respective shapes best shown in Fig. 7.

These parts are asesmbled on the cover plate 21 in the relationship shown in Figs. 8-13, in which the detent plate 33 is mounted on the cover plate by rivets 36 standing through the filler bar 32, with the actuating slide 31 interposed between the detent plate and the cover plate and slidable along the top of the filler bar, which serves as a bearing for it, and with the locking slide 30 also interposed between the detent plate and the cover plate but slidable along the top of the actuating slide 31.

A handle 38 extends upwardly from one end portion of the actuating slide 31 and projects through a slot 39 in the top front of the cover plate 21. Adjacent to this handle the slide 31 is cut out to provide an arcuate surface 40 of special radius as will be hereinafter explained, and the opposite end of the slide 31 has an inwardly turned car 41 perforated to receive one end of the coil spring 34.

The locking slide 30 has that end edge which is opposite and facing the arcuate surface 40 of the actuating slide 31, when the parts are assembled, provided with a similar arcuate surface, which may be mutilated or skeletonized as by consisting of the two short, spaced arcs 43 shown in Fig. 7. Proceeding inwardly from these arcs 43, the slide 30 has successively a lengthwise slot 44, a clockwise slot 45 into which the lengthwise slot opens, and another crosswise slot 46 spaced from and unconnected with the first one. An inturned ear or lug 47 may serve as an abutment stop on the edge of the slide 30 opposite the arcs 43 for limiting the movement of the slide, as will be explained.

The detent plate 33 has at its end which is adjacent to the slot 39, through which the handle 38 projects, an inturned lug or ear 50 perforated to catch the end of the spring 34 opposite the end thereof which is caught in the lug 41. The spring is held in tension between these two anchorages, thus biasing the actuating slide 31 to the extreme right hand limit of its movement permitted by the length of the slot 39, in which position it is shown in Fig. 8. The plate 33 has also a cut-out opening or window 52 in its intermediate area overlying the slot 26 in the front plate 21 through which the lug 25 is inserted to lock the cushion in inoperative position. The end of the plate 33 which is opposite that on which the lug 50 is located, has a catch lip or detent 53 turned outwardly, i. e., toward the cover plate 21 and hence toward the locking slide 30 which is interposed between the plates 33 and 21. Extending in this same outward direction, from the edge of the window 52 which is more remote from the detent 53, is a coin stop ear or lug 54 whose free end bears against the surface of the cover plate 21 and cooperates with the spacer bar 32 to maintain the spacing of the plates 33 and 21 so that the elements and 31 will have freedom to slide in that space.

The detent plate 33 is made of spring or resilient sheet metal and its edge adjacent the detent 53, which is at some distance from the rivets 36, is formed with an inturned cam projection 56. The free end of this projection lies within the range through which the finger 35 swings upon rotation of a key 57 fitted into the lock 58. That is to say, when such a key is turned so as to swing the finger 35 from the horizontal position in which it is shown in Figs. 9, 10, and 11 to the vertical position in which it is shown in Figs. 8 and 13, the finger cams under the projection 56 and lifts the detent plate, or the proximate end of the plate, so as to lift the detent 53 also from such portion of the locking slide 30 as it may be engaging and holding, thus freeing the locking slide for movement in the manner that will now be explained in connection with the operation of the device.

In operation:

The cushion pad is initially locked in the inoperative position as shown in Fig. 1. That is to say, the eye 7 has been slipped over the rod 8, the tongue 6 is folded up behind the body of the cushion pad, the lower end of the pad is pocketed between the rod 8 and the hook 11, and the lug 25 has been inserted into the slot 26 of the front cover plate 21. This has been done with the slot 45 of the locking slide 30 in register with the front cover plate 26, so that the lug 25 extends through the locking slide. Then in order to lock the lug in the two registering slots, the handle 38 is pushed in the slot 39 as far as possible to the left, as seen in Fig. 9. This thrusts the margins of the are 40 against the margins of the arc 43 and moves the locking slide slightly to the left, so that the lengthwise slot 44 now embraces the shank of the lug 25 as shown in Fig. 9 and holds the lug against withdrawal through the slot 26. The locking slide is held in this position because the detent 53 has dropped into the slot 46 and thereby kept the locking slide 30 from moving to the right when the handle 38 is released and the slide 31 is pulled to the right by contraction of the spring 34 which is anchored to the actuating slide 31 at 41 and to the detent plate 33 at 50. The parts are now in the position shown in Fig. 10, ready for insertion of a coin 60 (typically a twentyfive cent piece) into the slot 39 by a patron wishing to free the locked cushion for movement to the operative position shown in Fig. 2.

If the coin 60 be inserted into the slot 39 and the handle 38 be moved as far as possible to the left, against the contractile force of the spring 34, the coin will bridge the space between the arcs 40 and 43, as shown in Fig. 11, and thereby move the locking slide 30 farther to the left, as is shown in that figure, than it was possible for the actuating slide 31 to do with no coin interposed, as shown in Fig. 9. This additional movement resulting from the presence of the coin brings the full length of the lengthwise slot 44 past the shank of the lug 25, so that the lug is now standing in the large opening in the locking slide adjacent to the arcs 43, from which of course it can be pulled, passing also out through the slot 26 in the front cover plate 21, so that the cushion is released.

The patron then lifts the cushion up out of the pocket behind the hook 11 and pulls it up over the top surface of the seat bottom 4, which is then lowered to horizontal position, and the cushioned seat bottom is then ready for occupancy, as shown in Fig. 2. In this movement of the cushion, the eye 7 has slid somewhat up the rod 8 but of course remains attached to the rod so that the cushion continues to be captive on the fixed seat structure.

In the movement of the parts to the lug-releasing position of Fig. 11, the slot 46 of the locking slide 30 has slipped past the detent 53 on the edge of the detent plate 33 (which springs up slightly, by reason of its resilience, to permit this passing), and the detent 53 then snaps into the slot 45 at the end of the lengthwise slot 44. This holds the locking slide in its Fig. 11 or lug-releasing position even when the handle 38 is released and the spring 34 pulls the actuating slide 31 back to the right. Movement to the right is limited by contact of the inner left end surface 62 of the actuating slide 31 with the adjacent outer edge 63 of the locking slide (see Fig. 11). This prevents movement of the handle 38 to the right hand end of the slot 39, keeping the handle in an intermediate part of the slot and thus preventing removal of the coin from the slot.

The parts remain in this position during occupancy of the seat and until servicing after the seat is vacated. The service operator first removes the coin, which is done by inserting the key 57 into the lock 58 and turning it until the finger 35 lifts the camming finger 56 of the detent plate 33 to raise the detent 53 from the slot 45. This permits the spring 34 to pull the surface 62 against the surface 63 (see Fig. 11) until only the width of the lug 47 stands between the lug 41 and the adjacent edge of the detent plate 33, with the slot 45 of the locking slide 30 in register with the slot 26 in the front cover plate 21 and with the handle 38 seated at the far right hand end of the slot 39. In this position of the parts it is easy to pick the coin from the slot 39. This is done; the cushion is restored to its position shown in Fig. 1; the lug 25 is inserted into the registering slots 26 and 45; the key 57 is turned to its left hand limit (thus restoring the finger 35 to its horizontal position); and the handle 38 is pushed to its left hand limit. This movement of the handle pushes the locking slide 30 as far as it is permitted to move to the left with no coin interposed between the arcs 40 and 43, which is just enough to catch the lug 25 in the lengthwise slot 44 and to catch the detent 53 in the slot 46 as has been explained, so that the parts are restored to the position in which the cushion is locked in inoperative position and the coin box is ready to receive another coin for effecting another release of the cushion.

It will be evident that there are numerous mechanical equivalents that may be substituted for many of the parts, elements and sub-combinations that have been used to illustrate the foregoing embodiment of the invention shown in Figs.1-l3. Thus, for example, Figs. 14 and 15 show a modified form of connection for the coin box and the cushion slide rod in which the upper end of the rod 8a (corresponding to the rod 8 of Figs. 1-13), instead of being threaded as at 16 in Fig. 7 for reception of the length-adjusting nut 15, is corrugated or made like a rack, with parallel transverse ribs or flanges 90, so that a selected indentation between them may be clasped by the registering openings in the back plate 13 and the front plate 21 of the coin box, as shown, to determine the length of the rod.

Again, the cushion pad may be modified, as shown in Figs. 16-21, where the pad 5a has, sewed or otherwise secured to its edge which is uppermost in the inoperative locked position of the pad and which is at the rear in the operative position, an extension 92 which may be thin, i. e., single-ply fabric and unpadded, for covering the seat back when disposed for occupancy. As shown, this back-covering extension 92 may be made somewhat longer than the seat back, so that it folds over the top of the back as shown in Fig. 21, and a loop 93 may be provided at approximately the fold line. In the inoperative position of the cushion shown in Fig. 18 this loop is caught over a short post 94 which is added to the bracket 9a, best shown in Fig. 18, from which it slips when the cushion is unlocked. This permits the extension 92 to be freed with the pad and to be swung up over the chair back to the position shown in Fig. 21.

In the foregoing description and explanation of a preferred embodiment of the invention the pad has been described with emphasis on its seat-cushioning characteristics. However, it has been found in actual practice of the invention that an important advantage of the pad is its capacity to indicate, by being disposed in the operative position, that the seat is occupied, i. e., that it has been engaged by a patron even though the patron may be temporarily absent. To this end it is advantageous to inscribe the top surface of the pad with some indicative legend, such as the word Occupied, and of course it is not necessary, in order to obtain this advantage, that the pad have any cushioning characteristics. A plain, single ply of fabric, such as textile material or imitation leather, is suflicient. For this reason the appended claims are not to be considered limited to combinations including a pad of any special degree of softness even when they designate the pad as being a cushion pad.

Other and further changes may be made in the details of the illustrated constructions. The appended claims, which are directed to the various combinations of means which characterize the inventive improvement, are therefore not to be considered limited to the specific forms shown in the drawings and explained in this specification unless required by the express wording of the claims or the state of the prior art.

I claim:

1. A cushion attachment for a stadium or similar seat comprising a cushion pad, means permanently connecting the front end portion of the pad to the under side of a seat bottom for swinging movement between inoperative position adjacent said under side and operative position on the upper surface thereof, and coincontrolled means fixed to the under side of the front end portion of the seat bottom and including a bolt normally receiving and holding the rear end portion of the pad and being releasable to free said rear end portion of the pad for movement on said permanent connecting means to operative position.

2. A cushion attachment for a stadium or similar seat comprising a cushion pad, a coin-box attached to the front portion of the under side of a seat bottom, a flexible member permanently connecting the front portion of the pad to the coin-box, and coin-controlled mechanism in the coin-box including a bolt normally receiving and holding the rear end portion of the pad beneath the under side of the seat bottom and releasable to free the rear end portion of the pad whereby the pad may be pulled to operative position overlying the upper surface of the seat bottom while held connected to the coin-box by said flexible member.

3. A cushion attachment for a stadium or similar seat comprising a cushion pad, a flexible tongue having one end connected to the front end of the pad and having an eye at its other end, means permanently connecting said eye to a seat bottom for movement of the pad between inoperative position adjacent the under side of the seat bottom and operative position on the upper surface thereof, and coin-controlled means mounted on the front end portion of the under side of the seat bottom including a bolt directly receiving and securing the rear end of the pad to the seat bottom and releasable to free the pad for swinging movement around the front end of the seat bottom to operative position on the upper side thereof with the flexible tongue covering said coin-controlled means.

4. In a cushion attachment for a stadium or similar seat, means permanently connecting a cushion pad to a seat bottom for movement between inoperative position adjacent the under side of the seat bottom and operative position on the upper surface thereof, a fitting carried by the rear end portion of the pad, a bolt mounted on the seat bottom and cooperating with the fitting for holding the pad in inoperative position, and means for withdrawing the bolt from the fitting to release the pad for movement to operative position.

5. In a cushion attachment for a stadium or similar seat, flexible means permanently connecting the front end portion of a pad to a seat bottom, a fitting carried by the rear end portion of the pad, a bolt mounted on the under side of the seat bottom and cooperating with the fitting for holding the pad in inoperative position against the under side of the seat bottom, and means for withdrawing the bolt from the fitting to release the pad for swinging movement on said flexible connecting means to operative position on the upper surface of the seat bottom.

6. In combination with a seat bottom member having a locking device secured to its under side adjacent the front edge thereof, an elongated rod-like element extending tom the locking device rearwardly toward the back of the seat bottom member, and a cushion pad normally locked in inoperative position adjacent the under side of the seat and releasable for movement to operative position on the upper side of said member, said pad having means at its operative position rear edge engaged with said locking device in the inoperative position of the pad and having a flexible extension projecting from its operative position front edge slidably connected to the rod-like element and folded against the pad in the inoperative position thereof, whereby on release of the locked means the flexible extension may be slid forwardly on the rod-like element and the pad may be pulled over the front edge of the seat bottom member and disposed in operative position on the upper side of the member with the flexible extension holding the pad captive on the rod-like element.

7. In combination with a seat bottom member, a cushion pad normally disposed in inoperative position adjacent the under side of the member and movable to operative position on the upper side thereof, and means connecting the pad to the member for locking in inoperative position and release for movement to operative position comprising a locking device secured to the under side of the member adjacent the front edge thereof, means lockingly engageable with said device projecting from that edge portion of the pad which is adjacent the device when the pad is in inoperative position, and means extending from the opposite edge portion of the pad and operatively connected with the device for sliding movement and captive retention of the pad relatively to the device and member.

8. The combination claimed in claim 7, in which the locking device is coin-controlled and includes a coinreceiving slot adjacent the front edge of the seat bottom member, and in which said means extending from said opposite edge portion of the pad is a flexible tongue adapted to extend around the locking device and cover the slot when the pad is in operative position.

9. A cushion attachment for a stadium or similar seat comprising a cushion pad provided at its rear end with a fitting, a flexible tongue having one end connected to to the front end of the pad and having an eye at its other end, means permanently connecting said eye to a seat bottom for movement of the pad between inoperative position adjacent the under side of the seat bottom and operative position on the upper surface thereof, and coin-controlled means mounted on the scat bottom and including a bolt normally holding said fitting and releasable to free said fitting and release the pad for swinging movement around the front end of the seat bottom to operative position on the upper side thereof.

10. The combination claimed in claim 9, including clamping means attaching the coin-controlled means to the seat bottom, and a keeper carried by the clamping means, the fitting being insertible into the keeper when the pad is in inoperative position, and the bolt penetrating the keeper and releasably locking the fitting therein.

References Cited in the file of this patent UNITED STATES PATENTS 10 Horn Sept. 18, 1928 Horn May 24, 1949 Horn July 12, 1949 Kinney Dec. 4, 1951 Baer et a1. Nov. 11, 1952 FOREIGN PATENTS Germany Jan. 22, 1913 

